Control for loom letoff



Aug. 16, 1955 LARAlA ET AL 2,715,421

CONTROL FOR LOOM LETOFF Filed Dec. 21, 1953 1 INVENTORS ARTEMIO LARAIA VlCTOR F. SE PAVICH 4 Tia w g ATTORNEY CONTROL non LooM LETOFF Artemio Laraia and Victor F. Sepavich, Worcester, Mass, assignors to Crompton & Knowles Loom Works, Worcester, Mass, a corporation of Massachusetts Application December 21, 1353, Serial No. 399,452

14 Claims. (Cl. 139-109) This invention relates to controls for warp letoifs more particularly in looms and it is the general object of the invention to provide means for preventing the letofi from paying off warp after the loom has been stopped.

A type of letotf mechanism which has gone into general use employs a train of gearing operatively connected to the warp beam and including an escapement mechanism one part of which oscillates in order to let the other part thereof turn when warp is to be payed off. A friction brake for the oscillating part of the escapement means is under control of the whip roll and is moved to non-braking position whenever the warp tension causes the whip roll to move forwardly to or in front of a given position. When the brake is in non-braking position the oscillating part of the escapement means can rock to enable the beam to turn to pay off warp and thereby reduce warp tension.

It is found that under certain conditions the jarring and vibration of the loom incident to its stoppage is likely to cause undesired movements of the oscillating part of the escapement means permitting the warp beam to pay off excess warp which reduces the warp tension below the permissible minimum. One condition which can have this Lie Patent eifect arises if the weaver stops the loom manually at a time when the lay is forward and places the warp under a momentary increase in tension due to beat-up, thereby moving the whip roll forwardly far enough to release the brake.

It is an important object of the present invention to provide means normally inactive with respect to the oscillating part of the escapement means but brought into action upon loom stoppage to prevent vibration of the aforesaid part of the escapement means which would otherwise occur.

It is a further object of the invention to provide a stop or dampener means for the oscillating part of the escapement means which is normally in non-arresting position to permit unimpeded movement of the oscillating part of the escapement means when the loom is running but controlled by the loom stopping means so that it moves into arresting position with respect to the oscillating part of the escapement means whenever the loom is stopped before the vibration of the loom incident to its stoppage can be communicated to the oscillating part.

It is a still further object of the invention to provide an electrical control by means of which the arresting means is held in non-arresting position during loom operation but is released to move to arresting position immediately upon movement of the shipper handle to stopping position due to opening of the circuit of the electric control by the shipper handle. The arresting means is shown herein as being in the form of an eccentric closely adjacent to the path of movement of the oscillating member, but the invention is not necessarily limited to the eccentric.

It is a still further object of the invention to provide a unit to control oscillation of the rocking part of the escapement means and so constructed that it can be readily secured to a loom.

A further object is to provide manually controlled means by which the arresting means can be moved to 2,715,421 Patented Aug. 16, 1955 non-arresting position after the loom has been stopped.

In order that the invention may be clearly understood reference is made to the accompanying drawings which illustrate by way of example the embodiments of the invention and in which:

Fig. 1 is a side elevation of the rear part of a loom having the invention applied thereto.

Fig. 2 is an enlarged horizontal section on line 2-2, Fig. 1,

Fig. 3 is an enlarged detailed transverse section through the eccentric,

Fig. 4 is a vertical section on a reduced scale on line 44', Fig. 2, showing the eccentric in non-arresting position,

Fig. 5 is a vertical section on line 5-5, Fig. 2,

Fig. 6 is an enlarged side elevation of a part of Fig. 1 showing the connection between the core of the solenoid and the eccentric,

Fig. 7 is a diagrammatic view similar to Fig. 4 but showing the eccentric in arresting position, and

Fig. 8 is a diagrammatic view showing an electric circuit used in connection with the invention.

Referring particularly to Fig. 1, the loom frame 1 has mounted thereon a shipper shaft to which is secured a shipper handle 3 for controlling operation of the loom. An arm 4 fixed with respect to the shaft is connected to a link 5 which in turn is connected to a bell crank lever 6 pivoted at 7. A rod 8 extends rearwardly from the bell crank lever and operates an electric switch S which may be of any approved construction. As shown in Fig. 1, the shipper handle 3 is in running or driving position and the switch will be closed, but when the loom is stopped the shipper handle will be moved to the left to its stopping position with resultant opening of switch S.

Behind the loom is an upright 10 which together with the loom supports a channel iron 11 having a vertical web 12 and top and bottom flanges 13 and' 14, respectively. Secured to the flange 13 and extending upwardly therefrom is a casing 15 containing a nest of gearing operatively connected to the warp beam B which is journaled at 16 for rotation on a stand 17 secured to the upright 10. The beam has secured. thereto a sprocket wheel 18 meshing with a chain 19 engaging an adjustable idler 20 and then extending upwardly and around a sprocket wheel 21 rotatable on the casing 15. Fixed with respect to the sprocket wheel is a gear 22 which meshes with a pinion 23 rotatable on the casing and fixed with respect to another gear 24 which in turn meshes with a pinion 25.

The casing 15 supports an escapement means, designated generally at E, including an escapement wheel fixed with respect to and turning with pinion 25 and including also an oscillating member 31 the pallet or double pawl 32 of which cooperates with the wheel 30. The escapement member 31 is pivoted to the casing 15 at 33 and has a part 34 thereof extending downwardly for attachment to a dampening weight 35. The latter is secured to the part 34 by a bolt 36 and is provided primarily for the purpose of preventing the member 31 from oscillating too rapidly during loom operation. The pallet 32 and parts 34 and may be considered as the oscillating part of the escapement mechanism E.

The loom has a stationary guide roll 40 and a whip roll 41 mounted on a lever 42 the upper end of which is pivoted as at 43 to a small support 44 fixed with respect to the casing 15 or otherwise supported. A connector 45 attached at the lower end of lever 42 extends forwardly and is connected to a lever 46 which in turn is connected to a lever 47 pivotally mounted on a stationary stand 48. The lever 47 is connected to the lower end of a rod 49 having secured thereto a collar 50 to engage a brake 51. The upper end of the rod 49 is surrounded by a compression spring 52 and passes through a guide stand 53 secured to the top of the casing 15. The brake 51 has a shoe 55 for engagement with an arcuate brake flange 56 on the part 34 and concentric with axis 33. The warp W extends from the beam B over the guide roll and the whip roll 41 and then forwardly to provide the upper and lower warp sheets W1 and W2, respectively.

In operation, when the warp tension is at or near the permissible minimum the whip roll will be in rear position, to the left in Fig. l, and the rod 49 will be down so that spring 52 can hold the shoe 55 against the brake flange 56 and prevent oscillation of the escapement member 31. The escapement wheel is thus held against rotation and the gearing and the chain 19 operatively connected to it are held stationary to prevent angular movement of the warp beam. Consumption of the warp during the weaving operation increases its tension and the whip roll moves forwardly, the result of which through connector and lever 46 causes upward motion of rod 49 to cause movement of the shoe away from the flange 56. The member 31 will then be free to oscillate to permit the beam to rotate clockwise, Fig. 1, to pay off sufficient warp to reduce the warp tension. During the warp paying oif operation the oscillating part of the escapement mechanism rocks back and forth around the pivot 33 and this rocking will be arrested when the warp tension again approaches its permissible minimum to allow the shoe 55 to engage the flange 56.

The matter thus far described may be similar to letotfs shown in several prior patents, one of which No. 2,330,514 to Payne may be mentioned as an example. It is thought suflicient for present purposes to state that the escapement means E operates when the brake 51 is in the non-braking position to permit the beam B to turn and that if under these conditions the loom should be stopped there is likely to result a sutficient vibration to cause undesired oscillation of the member 31 which may result in paying off more warp than is desired.

The present invention has for its purpose to provide means to prevent oscillation of the member 31 when the loom is stopped. In carrying the invention into effect the channel iron 11 has secured thereto a unit U including a carrier 59 provided with two bearings 60 and 61 which are located respectively in front and back positions as viewed in Fig. 1. These bearing members support a shaft 62 to which is secured an arresting means shown here as an elongated eccentric 63 extending closely adjacent to the path of oscillation of the weight 35 and having a roughened surface 64 for engagement with a roughened plate 65 secured at 66 to the weight 35. Ordinarily the eccentric will be spaced from said path out of engagement with the plate 65, or in the position shown in Fig. 4, when the loom is in operation.

The means for holding the eccentric in its normal nonarresting position during loom operation is shown in Figs. 1, 2, 5 and 6 and includes an electromagnetic device shown here as a solenoid 70 held in any approved manner to the forward bearing 60. The solenoid is supported by a holder 71 having a plate 72, see Fig. 2, bolted at 73 to the bearing 60 and including a forward upright arm 74 and a cross bar 75 extending over the solenoid and connected to a depending arm 76. The lower ends of the arms 74 and 76 extend part way under the solenoid as at 77, and the holder 71 fits the solenoid closely enough to hold it in rigid position.

The solenoid has a core 80 which is pivoted at 81 to a link 82 the lower end of which is pivoted at 83 to an arm 84 which is freely rockable on a stud 85 secured to the bearing 60, as by being pinned thereto at 86, see Fig. 6. The hub 87 of arm 84 receives one end 88 of a torsion spring 89 surrounding stud 85 and having the other end 90 thereof extended into a collar 91 held in angularly adjusted position on the stud 85 by set screw i 92. The effect of the spring is to tend to turn the arm 3 in a counter-clockwise direction as viewed in Fig. 5, but the spring will be overpowered by the solenoid when the latter is energized. A second arm 93 is secured by set screw 94 to the shaft 62 and has a pin 95 thereon extending into a slot 96 in the arm 84.

A manually controlled electric switch M is supported by the bearing 60 and has a small handle 97 by which it can be moved temporarily from its normally open position to closed position.

Solenoid T 9 and the switches S and M are electrically connected as indicated diagrammatically in Fig. 8. A source of electric power P such as a transformer is connected to one side of the solenoid and the other side of the latter is connected by a wire 100 to pole 101 of the switch S. The other pole 102 of switch S is attached to the rod 8 and is connected to the opposite side of the power source P by wire 163. The normally open switch M is in parallel with the switch S by having its electrode 105 connected to wire 1510 and having its other electrode 1416 connected to wire 103. The solenoid 7d and spring 89 and the parts associated with them may be considered to be control means for the eccentric 63 and the latter may be considered to be an arresting means for the oscillating part 31.

When the loom is in operation and the shipper handle is in the driving or running position shown in Fig. 1 the switch S will be closed as indicated in Fig. 8 and the solenoid 70 will be energized so that the core 81 will be raised to hold arm 84 in its elevated position against the action of spring 89. When in this position arm 84 holds the arm 93 in the position shown in Fig. 5 to maintain the eccentric 63 in the non-arresting position thereof shown in Fig. 4. As soon as the shipper handle is thrown to the off or stopping position, see dotted lines Fig. 8, electrode 102 moves away from electrode 101 and the circuit for the solenoid is open, whereupon the spring 89 turns the arm 84 in a counterclockwise direction, Fig. 5, to rock arm 93 in a direction to turn the eccentric to the arresting position thereof shown diagrammatically in Fig. 7 against the plate 65. Engagement of the eccentric with the plate 65 will be sufficient to arrest any oscillation of the member 31 which might otherwise occur incident to stoppage of the loom, and the escapement means is prevented from operating, thus locking the beam B against turning.

If the cause of loom stoppage requires that the letotf be released the operator can close the switch M, where upon the solenoid will be reenergized and the eccentric will be moved from the position shown in Fig. 7 back to the non-arresting position shown in Fig. 4. Release of the handle 97 will result in opening the switch M whereupon the eccentric will return to arresting position.

From the foregoing it will be seen that the invention sets forth means by which the escapement mechanism of a letoff mechanism may be arrested upon stoppage of the loom to prevent the warp beam from turning sufficiently to pay off an excess of warp which might result in reducing warp tension to a point below the permissible minimum. It will be seen that the arresting mechanism for the oscillating member 31 includes an eccentric normally held positively in non-arresting position due to energization of the solenoid, but as soon as the shipper handle moves to stopping position the solenoid becomes deenergized and means, such as the spring 89, comes into action to turn the eccentric into the arresting position shown in Fig. 7. The actual stopping of the loom will occur slightly after the shipper handle has moved, but by that time the spring 89 will have thrown the eccentric to arresting position. The manually operated switch M can if desired be closed temporarily to reenergize the solenoid for the purpoe of moving the eccentric back to its nonarresting position. The control for the oscillating part 31 need not necessarily be exactly as shown, but when deenergization of the solenoid is relied upon to permit spring 89 to move the eccentric to arresting position, vibration which might occur during a period of loom stoppage, caused for instance by operation of adjacent looms, will not be able to cause rocking of the escapement member 31. Also, the invention provides the unit U which carries the parts which control member 31 and is so constructed that it can be readily applied to a loom.

Having now particularly described and ascertained the nature of the invention and in what manner the same is to be performed, what is claimed is:

1. In letoif mechanism for a loom having a warp beam and wherein oscillation of a part of an escapement means enables the beam to turn to pay off warp, arresting means for said part of the escapement means capable of assuming arresting and non-arresting positions with respect to said part, and control means for said arresting means effective to keep the arresting means in the non-arresting position thereof during loom operation to enable said part to oscillate but effecting movement of the arresting means to the arresting position thereof to prevent oscillation of said part when the loom is stopped.

2. The letotf mechanism set forth in claim 1 wherein the control means includes an electromagnetic device which is energized during loom operation but is deenergized when the loom stops.

3. The letoif mechanism set forth in claim 1 wherein the control means includes a spring which is overpowered during loom operation but is free to move the arresting means to arresting position upon stoppage of the loom.

4. The letoif mechanism set forth in claim 1 wherein the arresting means extends closely adjacent to the path of oscillation of said part and is spaced from said path when in non-arresting position but moves toward said path and against said part when moving to. arresting position.

5. The letofi": mechanism set forth in claim 1 wherein the arresting means is an eccentric rockable about an axis extending adjacent to the path of oscillation of said part of the escapement means and the control means acts to hold said eccentric in non-arresting position out of engagement with said part when the loom is running but rocks the eccentric to arresting position in engagement with said part when the loom stops.

6. The letofi mechanism set forth in claim 1 wherein manually controlled means are provided for the control means to effect return of the arresting means to the nonarresting position thereof when the loom is stopped.

7. In a loom having a warp beam and a shipper handle to assume running and stopping positions, letoif mecha' nism including a part of an escapement means which oscillates to enable the beam to turn to pay off warp, arresting means for said part capable of assuming either an arresting position to prevent oscillation of said part or a non-arresting position in which said part can oscillate, control means for said arresting means under control of said shipper handle effective when the latter is in running position to maintain the arresting means in the nonarresting position thereof and effective when the shipper handle moves to stopping position to move the arresting means to the arresting position thereof to prevent oscillation of said part.

8. The loom set forth in claim 7 wherein the control means includes an electromagnetic device and a switch therefor operatively connected to the shipper handle, the latter when in running position closing the switch to effect energization of the device and the shipper handle when in stopping position causing the switch to be open to deenergize said device.

9. The loom set forth in claim 8 wherein a second normally open manually operated switch is provided effective when closed during loom stoppage to energize said device.

10. A unit to control the oscillating part of an escapemerit means of a warp letoff mechanism, said unit including a carrier, an eccentric rotatably mounted on the carrier, an electromagnetic device supported on the carrier, means whereby energization of the device effects turning of the eccentric in one direction, and means on the carrier tending to turn said eccentric in the opposite direction.

11. The unit set forth in claim 10 wherein said device is a solenoid having a core operatively connected to an arm fixed with respect to the eccentric.

12. The unit set forth in claim 10 wherein the last named means is a spring one end of which is fixed with respect to the carrier and the other end of which is operatively connected to the eccentric.

13. The unit set forth in claim 10 wherein a stud is fixed with respect to the carrier and has an arm mounted thereon for free rotation operatively connected to the eccentric and has a collar secured thereto, and the last named means is a spring surrounding said stud having one end thereof connected to the collar and having the other end thereof connected to said arm.

14. The unit set forth in claim 13 wherein a second arm is fixed to the eccentric and has a pin and slot connection with the first arm and the device is a solenoid having a core connected to one of said arms.

References Cited in the file of this patent UNlTED STATES PATENTS 871,875 Lanning Nov. 26, 1907 2,330,514 Payne Sept. 28, 194-3 2,665,715 Beall et a]. Jan. 12, 1954 

